J. Phil Thien's Projects

I'm building a small all-in-one tophat style DC for use with 3 inch (max) hose.  What sort of off the shelf items can I use for the tangential inlet?  A couple times in the past I have taken PVC pipe and bandsawed a taper & glue/screw it to a plastic flange but that method is extremely fussy--but it's cheap :)
In this instance the cut away portion would also need to be curved to match the curvature of the tophat body.  Sounds like too much trouble to me.

Do most of you fab a rectangular box & then cut that to fit the curve?  Any other nifty ideas?

Where can I buy or how can I build a 6" ID bellmouth for my 2-stage impeller intake?  It really makes a lot of sense to me to ease the transition into the fan so I want to flare the intake--but not spend a bunch to do it.  I've considered mounting a section of 6" PVC on a lathe or drillpress & see if I can expand the mouth with a torch as it spins.  Also considered combing the aisles at Toys R Us for a plastic horn the right diameter.  Used baritones are still very expensive :) I've been eyeing kitchen departments when I'm with the wife...looking for a jello or cake mold with a large ID.  Etc.

Has anybody done this before or do I need to be the one?

I want to build a tophat separator to sit on a Brute trashcan.  I plan to attach a ring to the outside of the separator sleeve to rest on the rim of the can and for strength I'd like to place the baffle inside the sleeve at the same height as the outer ring & secure with screws through all.  Is there any downside to positioning the baffle up inside the sleeve a few inches?  I think this would be a lot easier than trying to size & place the baffle at an exact spot (touching) inside a tapered trashcan.

I'm planning to build a purpose-built DC using a 12.5" 3-stage blower (300cfm@15"wc) that's been gathering dust under my bench + a top hat style baffle for the blower to sit on.  This is for use in sucking up vermiculite that's in the attic of my 60 year old log cottage.  What's missing is about 40 feet of flex hose that I don't want to spend much money on :)
3" dryer hose might work on this one-time task but it's so flexible it might be aggravating to use (kinks, collapsing, rips from dragging over obstacles).

Any suggestions where to look for 2.5"-3" budget flex hose in bulk?

It's been stated that inlet angle & swarf flow direction doesn't matter.  I imagine that's true for a separator fed with hoses but what about when the baffle is mounted right on the fan housing?  Seems to me you would want the swirl to run the same direction as the impeller since it's so close it may be "coupled" to the air mass.

OR--is counter-rotation desirable in case it might reduce the amount of fines that get pulled in by the impeller?

Anybody ever play with this choice?

I'm a newbie to baffle concepts but definitely not new to home shop DC's.  My 2-stage 4" pvc system pre-dates the internet and works fine, despite all the grave warnings about dust explosions that were tossed about in the magazines back then :) 
Although I get very little fines in my bag (less than 5%), and none on the walls of the closet it's located in, I'd still like to try to improve performance.  I'm baffled (ha!) by posts I've read about the desired effect in the drum.  Some posts talk about wanting a dead drum where chips just fall down while other posts talk about spinning the chips out in a vortex.

Which is the intended effect of a Thien baffle?